Your email to T was honest and where you were at that moment.
Her reply to you was emotionally out of control.
Of the 2 of you, T and you, T is the one who should be able to control her emotions. Not that she shouldn't tell you that the email sounded angry, but that she should have left her reaction out of it, and helped you explore that anger...it was directed her way, not at her, because you were angry and because you felt safe expressing these things to her.

Her response was neither helpful nor therapeutic.

That must have been really really hard to go to your next session.
What kind of feedback is helpful? Any. Everything you said here.

I have given my T feedback and I felt really guilty about doing it because it felt like whining, complaining, criticizing, etc. When I said that's how it felt, her face lit up and she said that it is very helpful to get feedback to know how we are doing and to learn more about me. (yikes. lol).